Physiology Of Bone

Front 1

Where is Calcitonin produced?

Back 1

in the thyroid gland

Front 2

Where is Parathyroid Hormone (PTH) produced?

Back 2

in the parathyroid (pth) glands

Front 3

What are the organic components of bone?

Back 3

1--Bone Cells
osteoblasts,
osteocytes
osteoclasts
2--Osteoid

Front 4

Describe Osteoblasts.

Back 4

--immature bone cell that secretes the organic component of the matrix
--found in all bone surfaces
--serves as a framework for the deposition of calcium and phosphate salts

Front 5

Describe Osteocytes.

Back 5

--mature bone cells that maintain the matrix

Front 6

Describe Osteoclasts.

Back 6

--giant multinucleate bone cells that secrete acids and enzymes to dissolve the bone matrix
--contain large #s of mitochondria and lysosomes

Front 7

What is Osteoid?

Back 7

--the organic part of the matrix onto which calcium can be deposited
--contains polysaccharides, GAGS, and collagen
--contributes to the resiliance and toughness of bones

Front 8

What are the INorganic components of bone? Function?

Back 8

--calcium and phosphorus salts (80% is calcium phosphate; the rest are calcium carbonate and magnesium phosphate)
Function: provides hardness and rigidity to bone

Front 9

How does a bone become soft and flexible?

Back 9

--removing the INorganic component by soaking in dilute acid

Front 10

How does a bone become brittle?

Back 10

--removing the organic component by charring
--inorganic salts remain though

Front 11

Lacunae

Back 11

the cavities containing the osteocyte bone cells

Front 12

Lamellae

Back 12

circular rings around the central canal

Front 13

Canaliculi

Back 13

tiny canals that radiate from the central canal to lacunae; forms a transport system

Front 14

Ossification

Back 14

formation of true bone by deposition of calcium salts in a matrix of osteoid tissue

Front 15

Calcification

Back 15

depositing calcium salts within tissues

Front 16

What is the difference between Endochondral and Intramembranous Ossification?

Back 16

EO--occurs in long bones
IO--occurs in flat bones

Front 17

Where are the ossification centers located in a long bone?

Back 17

Primary--located in midshaft region (diaphysis)
Secondary--each located in epiphysis (proximal and distal)

Front 18

What is Bone Remodeling?

Back 18

the continous turnover of bone

Front 19

What is a Fracture?

Back 19

a break in the continuity of bone

Front 20

List the 6 types of Fractures of bones.

Back 20

1--simple
2--open
3--greenstick
4--complete
5--physeal
6--comminuted

Front 21

Simple Fracture

Back 21

skin stays intact; unbroken

Front 22

Open Fracture

Back 22

bone is exposed through the skin; not intact

Front 23

Greenstick Fracture

Back 23

one side of bone is broken/splintered, while other side is intact but bent
**happens in younger animals

Front 24

Complete Fracture

Back 24

bone is broken across

Front 25

Physeal Fracture

Back 25

a fracture located at the junction of an epiphysis and diaphysis

Front 26

Comminuted Fracture

Back 26

bone is broken into many smaller pieces or shards

Front 27

List the steps in the healing of a fracture.

Back 27

**Upon apposition + immobilization, healing can occur.
1--clot is invaded by CT cells; granulation tissue
2--osteoblasts divide and produce a large amount of osteoid; callus
3--mineralization of callus
4--spontaneous deformity correction

Front 28

In regards to the healing of a fracture, the amount of spontaneous correction depends on what?

Back 28

1--age of animal
2--blood supply to bone
3--degree of correction required
4--presence or absence of infection
5--amount of damage to associated tissues
**younger animals heal quicker than older animals**

Front 29

Bone TB

Back 29

--causes erosion of bone tissue
--infection caused by Mycobacterium tuberculosis
--attacks the spine and ends of long bones

Front 30

Osteomyelitis

Back 30

--inflammation of bone and bone marrow
--caused by Staphylococcus/Steptococcus

Front 31

Osteodystrophy

Back 31

--any abnormality of bone development
--abnormality in normal Ca and P regulation

Front 32

Rickets and Osteomalacia

Back 32

--inadequate mineralization of osteoid; due to lack of Vitamin-D
**Rickets--young animals
**Osteomalacia--adult animals

Front 33

Achondroplasia

Back 33

--hereditary condition in which metaphyses fuse early but bones continue to grow in diameter
--seen in dachshund dogs and cattle